Sound Deadening and the most beneficial spots to target

I have done sound treatments and audio upgrades to many many cars (and homes)over the years. Unlike most I havent been disapointed in the JBL sound system that came in my truck, but I was sure it could benefit from some key sound deadening and absorption areas. This thread will just be me documenting some of that process and letting you guys know what I found to give the most return for my efforts.

Under the hood:
I am a big fan of turbo inline engines, however this one is a bit a noisy and not in a good way. My first attempt to quiet it down was with an engine cover. This had no noticable result in the cab, or from outside of the truck. I applied a close cell adhesive back foam to hopefully absorb some noises. Approximately 5k miles on the truck since this was installed.

I was hesitant to use underhood sound deadener, as the heat seems like it could be an issue. But I have seen many utilize it with success, and the deadener I purchased is rated for underhood use.

Under the hood (again):

This time I removed my factory underhood material that is intended to quiet the engine. Gave it a quick wipe down, and installed some small peices of 3 layer deadener to the outer sheet metal, then full size sheets to the inner. Then reinstalled the hood liner. This had GREAT results and I highly reccomend this if you find the engine noise not to your liking.

Going to give it a shot @Drifte

This is what Ive been using. I have an update on the door treatment to post here soon, but I also do a layer of closed cell foam over this deadener combo.

https://www.amazon.com/dp/B0B6JKF9SC?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1

Drifte said:

I have an update on the door treatment to post here soon,

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Thank you, looking forward to that. I’ve got a roof rack and I’m looking to kill some of the wind noise. Though it’s not bad (especially with music on), cutting down on some of it would help.

aha, mine looks exactly the same. i used siless max tho

Is the Siless stuff heavy? Think it would give Redline hood struts a problem?

hagglethorn said:

Is the Siless stuff heavy? Think it would give Redline hood struts a problem?

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I was actually going to add the hood struts, but havent yet so I cant speak to that. I dont forsee an issue as it didnt add much weight overall. I could weigh a square this weekend and tell you exactly how much we put on there.

I didnt take great photos of the doors unfortunately. But they are typical to most door panels for removal.

At this stage I only did the outer skin of the door. I find this has the largest impact on road noise and improving the sound from the door speakers (biggest bonus). 4 full sheets of the 3 layer deadener and then I cover that with the closed cell foam (here: https://www.amazon.com/dp/B07B75PD8B?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1).

Typically I would also had a foam ring to seal the door speaker to the door panel for a drastic improvement in midbass, however Toyota already did this from the factory.

The result of doing the doors I noticed a slight decrease in road noise, but a nice boost in sound quality from the doors. I will do the same treatment to the rear doors. This leaves the roof, back wall, floors and front inner fender to do.

hagglethorn said:

Is the Siless stuff heavy? Think it would give Redline hood struts a problem?

Click to expand...

From the picture that Drifte posted, I can tell you my hood has practically the same layout of sound deadener. I have the no name brand hood struts installed, and it is not an issue, it actually counter balances it a bit better rather than the hood popping up all squirrely it does it nice n smooth. On the way down, less effort is now needed to get the hood fully closed. Still has a somewhat loud sound, but less than before, and a small kind of thud closing .